plugin-103 cocoa auto layout

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Session 103

Cocoa Autolayout

Ken FerryCocoa Frameworks

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Layout

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Springs and Struts

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AutolayoutSprings and Struts

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Autolayout

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Autolayout

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Benefits

• Reduced need for in-code layout—IB goes further

• Improved in-code layout• Design flexibility• Localization• Resolution independence

7

Basics

Runtime

Layering

Debugging

Transition

Agenda

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Interface Builder: Simplicity and expressivenessDemo

Kevin CatheyInterface Builder

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Guide -> NSLayoutConstraint

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y = m·x + b

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view1.attr1 = m·view2.attr2 + b=

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view1.attr1 = m·view2.attr2 + b=

acceptButton.left = cancelButton.right + 12

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view1.attr1 = m·view2.attr2 + b=≥≤

@ priority

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[NSLayoutConstraint constraintWithItem: attribute: relatedBy: toItem: attribute: multiplier: constant: ]

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[NSLayoutConstraint constraintWithItem:acceptButton attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEquals toItem:cancelButton attribute:NSLayoutAttributeRight multiplier:1.0 constant:12]

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ASCII Art!

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Cancel Accept

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Cancel Accept

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[cancelButton]-[acceptButton]

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[NSLayoutConstraint constraintsWithVisualFormat:@”[cancelButton]-[acceptButton]”_

options:0 metrics:nil views:viewsDictionary];

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[cancelButton _]-[acceptButton]

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[cancelButton _]- [acceptButton ]-

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[cancelButton(72)]-12-[acceptButton(50)]

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[cancelButton(72)]-12-[acceptButton(50)]

viewpredicate

connection

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Standard Space

Inequality, Priority

Connection to Superview

Vertical Layout

Flush Views, Equal Widths

Multiple Predicates

Combination

[button]-[textField]

[wideView(>=60@700)]

|-5-[contentView]-5-|

V:[topView]-10-[bottomView]

[redBox][yellowBox(==redBox)]

[flexibleView(>=30,<=80)]

|-[Find]-[FindNext]-[FindField(>=20)]-|

Visual Format Language


8 pts

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Standard Space



Vertical Layout


Multiple Predicates

Combination









wideView

60 pts[wideView(>=60@700)]

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Standard Space



Vertical Layout


Multiple Predicates

Combination









contentView 5 pts5 pts

superview


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Standard Space



Vertical Layout


Multiple Predicates

Combination









topView

10 pts

bottomView


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Standard Space



Vertical Layout


Multiple Predicates

Combination









redBox yellowBox


30

Standard Space



Vertical Layout


Multiple Predicates

Combination









flexibleView

30 pts80 pts


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Standard Space



Vertical Layout


Multiple Predicates

Combination









superview

8 pts8 pts 20 pts20 pts20 pts


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viewsDictionary

[NSLayoutConstraint constraintsWithVisualFormat:@”[cancelButton]-[acceptButton]”_

options:0 metrics:nil views: ];viewsDictionary

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(gdb) po viewsDictionary{ acceptButton = "<NSButton: 0x4004c8660>"; cancelButton = "<NSButton: 0x4004a9ec0>";}

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Basics

Runtime

Layering

Debugging

Transition

Agenda

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Constraints at Runtime

-[NSView addConstraint:]-[NSView removeConstraint:] Superview

Button Button

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Phases of Display

Display

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Phases of Display

Display

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Phases of Display

DisplayLayoutUpdate Constraints

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Display

-[NSWindow displayIfNeeded]

-[NSView displayIfNeeded]

-[NSView drawRect:]

-[NSView needsDisplay]

-[NSView setNeedsDisplay:]

Update Constraints

-[NSWindow updateConstraintsIfNeeded]

-[NSView updateConstraintsForSubtreeIfNeeded]

-[NSView updateConstraints]

-[NSView needsUpdateConstraints]

-[NSView setNeedsUpdateConstraints:]

Phases of Display

Layout

-[NSWindow layoutIfNeeded]

-[NSView layoutSubtreeIfNeeded]

-[NSView layout]

-[NSView needsLayout]

-[NSView setNeedsLayout:]

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Layout PhaseCalls -[NSView setFrame:]

• Code should modify constraints, not frames

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Mutation and Animation

[NSAnimationContext!beginGrouping];[[NSAnimationContext!currentContext]!setDuration:1.0];[[constraint!animator]!setConstant:800];[NSAnimationContext!endGrouping];

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Basics

Runtime

Layering

Debugging

Transition

Agenda

43

View vs Controller Responsibilities Reworking the layering

• setFrame: is monolithic■ If view state changes, layout never updates

• Controller layer has to know a lot about visual design of views

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Baselines

• NSView:-(CGFloat)baselineOffsetFromBottom;

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Alignment Rect

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Alignment Rect

• NSView:- (NSEdgeInsets)alignmentRectInsets;

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Intrinsic Content Size

• Intrinisic Content Size declares size of content■ Invalidate when attributes change

• Inverts classic Cocoa sizeToFit■ Greatly reduces burden on controller layer■ Lets view layer vary independently■ Makes work done in Interface Builder go further

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Intrinsic Content Size

• External controller knows more about importance

-setContentCompressionResistancePriority:forOrientation:

-setContentHuggingPriority:forOrientation:

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Intrinsic Content Size vs Fitting Size

Intrinsic Content Size Fitting Size

Override Call

Feeds data into layout system

Takes data out of layout system

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Basics

Runtime

Layering

Debugging

Transition

Agenda

51

Working with Autolayout in codeDemo

Ken FerryCocoa Frameworks

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Debugging

• Find bad view frame-NSShowAllViews YES

-[NSView _subtreeDescription]

• Bad view frame -> bad constraint-[NSView constraintsAffectingLayout:forOrientation:]

-[NSWindow visualizeConstraints:]

• Bad constraint -> bad code■ Instruments template, “Cocoa Layout”

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Debugging

54

Basics

Runtime

Layering

Debugging

Transition

Agenda

55

Transition-[NSView translatesAutoresizingMaskIntoConstraints]

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TransitionAutolayout activates lazily

LayoutUpdate Constraints Display

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Review• Reduced need for in-code layout

■ Constraints accommodate dynamic content

• Improved in-code layout■ ASCII art, improved layering

• Design flexibility■ Baselines, alignment rect, intrinsic content size

• Localization■ Dynamic content, intrinsic content size

• Expressiveness■ Peer to peer relationships, inequalities, priority

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Bill DudneyCocoa [email protected]

Autolayout Documentation, Sample Code, and Release NotesLog in and search for ‘Autolayout’ on Mac Dev Centerhttps://developer.apple.com/library/prerelease/mac/search/?q=Autolayout

Programming With ConstraintsThe Cassowary Linear Arithmetic Constraint Solving Algorithm http://www.cs.washington.edu/research/constraints/cassowary/

Apple Developer Forumshttp://devforums.apple.com

More Information

61

Using Interface Builder in Xcode Pacific HeightsTuesday 2:00PM

Related Sessions

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Labs

Cocoa Lab App Frameworks Lab ATuesday 2:00-6:00PM

Cocoa and Autolayout Lab App Frameworks Lab AWednesday 9:00-11:00AM

Cocoa, Full Screen, and Aqua Lab App Frameworks Lab AWednesday 2:00-6:00PM

Cocoa, Auto Save, File Coordination, and Resume Lab App Frameworks Lab AThursday 2:00-4:00PM

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